Error-tolerant design
Encyclopedia
An error-tolerant design is one that does not unduly penalize user errors. It is the human equivalent of fault tolerant design that allows equipment to continue functioning in the presence of hardware faults, such as a "limp-in" mode for an automobile
electronics unit that would be employed if something like the oxygen sensor
failed.
s is one technique in error-tolerant design. An example is the interlock
or lockout of reverse in the transmission
of a moving car. This prevents errors, and prevention of errors is the most effective technique in error-tolerant design. The practice is known as poka-yoke
in Japan where it was introduced by Shigeo Shingo
as part of the Toyota Production System
.
in computer
software for an action that could have severe consequences if made in error, such as deleting a file (although the consequence of inadvertent file deletion has been reduced from the DOS
days by the concept of the recycle bin
in Microsoft Windows
or the trash can in Mac OS
that has been introduced in most GUI
interfaces
). Adding too great a mitigating factor in some circumstances can become a hindrance, where the confirmation becomes mechanical this may become detrimental - for example, if a prompt is asked for every file in a batch delete, one may be tempted to simply agree to each prompt, even if a file is deleted accidentally.
Another example is Google
's use of spell checking on searches performed through their search engine. The spell checking minimises the problems caused by incorrect spelling by not only highlighting the error to the user, but by also providing a link to search using the correct spelling instead. Searches like this are commonly performed using a combination of edit distance
, soundex
, and metaphone
calculations.
Automobile
An automobile, autocar, motor car or car is a wheeled motor vehicle used for transporting passengers, which also carries its own engine or motor...
electronics unit that would be employed if something like the oxygen sensor
Oxygen sensor
An oxygen sensor, or lambda sensor, is an electronic device that measures the proportion of oxygen in the gas or liquid being analyzed. It was developed by the Robert Bosch GmbH company during the late 1960s under the supervision of Dr. Günter Bauman...
failed.
Use of behavior shaping constraints to prevent errors
Use of forcing functions or behavior-shaping constraintBehavior-shaping constraint
A behavior-shaping constraint, also sometimes referred to as a forcing function or poka-yoke, is a technique used in error-tolerant design to prevent the user from making common errors or mistakes. One example is the reverse lockout on the transmission of a moving automobile.The microwave provides...
s is one technique in error-tolerant design. An example is the interlock
Interlock (engineering)
Interlocking is a method of preventing undesired states in a state machine, which in a general sense can include any electrical, electronic, or mechanical device or system....
or lockout of reverse in the transmission
Transmission (mechanics)
A machine consists of a power source and a power transmission system, which provides controlled application of the power. Merriam-Webster defines transmission as: an assembly of parts including the speed-changing gears and the propeller shaft by which the power is transmitted from an engine to a...
of a moving car. This prevents errors, and prevention of errors is the most effective technique in error-tolerant design. The practice is known as poka-yoke
Poka-yoke
' is a Japanese term that means "fail-safing" or "mistake-proofing". A poka-yoke is any mechanism in a lean manufacturing process that helps an equipment operator avoid mistakes . Its purpose is to eliminate product defects by preventing, correcting, or drawing attention to human errors as they...
in Japan where it was introduced by Shigeo Shingo
Shigeo Shingo
, born in Saga City, Japan, was a Japanese industrial engineer who distinguished himself as one of the world’s leading experts on manufacturing practices and the Toyota Production System. Shingo is known far more in the West than in Japan, as a result of his meeting Norman Bodek, an American...
as part of the Toyota Production System
Toyota Production System
The Toyota Production System is an integrated socio-technical system, developed by Toyota, that comprises its management philosophy and practices. The TPS organizes manufacturing and logistics for the automobile manufacturer, including interaction with suppliers and customers...
.
Mitigation of the effects of errors after they are made
The next most effective technique in error-tolerant design is the mitigation or limitation of the effects of errors after they have been made. An example is a checking or confirmation function such as an "Are you sure" dialog boxConfirmation dialog box
Confirmation dialog is a dialog box that asks user to approve requested operation. Usually this dialog appears before a potentially dangerous operation is performed...
in computer
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...
software for an action that could have severe consequences if made in error, such as deleting a file (although the consequence of inadvertent file deletion has been reduced from the DOS
DOS
DOS, short for "Disk Operating System", is an acronym for several closely related operating systems that dominated the IBM PC compatible market between 1981 and 1995, or until about 2000 if one includes the partially DOS-based Microsoft Windows versions 95, 98, and Millennium Edition.Related...
days by the concept of the recycle bin
Recycle bin (computing)
In computing, the trash is temporary storage for files that have been deleted in a file manager by the user, but not yet permanently erased from the physical media...
in Microsoft Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
or the trash can in Mac OS
Mac OS
Mac OS is a series of graphical user interface-based operating systems developed by Apple Inc. for their Macintosh line of computer systems. The Macintosh user experience is credited with popularizing the graphical user interface...
that has been introduced in most GUI
Gui
Gui or guee is a generic term to refer to grilled dishes in Korean cuisine. These most commonly have meat or fish as their primary ingredient, but may in some cases also comprise grilled vegetables or other vegetarian ingredients. The term derives from the verb, "gupda" in Korean, which literally...
interfaces
User interface
The user interface, in the industrial design field of human–machine interaction, is the space where interaction between humans and machines occurs. The goal of interaction between a human and a machine at the user interface is effective operation and control of the machine, and feedback from the...
). Adding too great a mitigating factor in some circumstances can become a hindrance, where the confirmation becomes mechanical this may become detrimental - for example, if a prompt is asked for every file in a batch delete, one may be tempted to simply agree to each prompt, even if a file is deleted accidentally.
Another example is Google
Google
Google Inc. is an American multinational public corporation invested in Internet search, cloud computing, and advertising technologies. Google hosts and develops a number of Internet-based services and products, and generates profit primarily from advertising through its AdWords program...
's use of spell checking on searches performed through their search engine. The spell checking minimises the problems caused by incorrect spelling by not only highlighting the error to the user, but by also providing a link to search using the correct spelling instead. Searches like this are commonly performed using a combination of edit distance
Edit distance
In information theory and computer science, the edit distance between two strings of characters generally refers to the Levenshtein distance. However, according to Nico Jacobs, “The term ‘edit distance’ is sometimes used to refer to the distance in which insertions and deletions have equal cost and...
, soundex
Soundex
Soundex is a phonetic algorithm for indexing names by sound, as pronounced in English. The goal is for homophones to be encoded to the same representation so that they can be matched despite minor differences in spelling. The algorithm mainly encodes consonants; a vowel will not be encoded unless...
, and metaphone
Metaphone
Metaphone is a phonetic algorithm, an algorithm published in 1990 for indexing words by their English pronunciation. It fundamentally improves on the Soundex algorithm by using information about variations and inconsistencies in English spelling and pronunciation to produce a more accurate...
calculations.